mmc ioctl for hw reset ,partitiing, enhanced area setting, boot partition update.

mmc ioctl for hw reset ,partitiing, enhanced area setting, boot partition update.

[NamJae Jeon]

Dear. Chris.

you know, there is no method to use emmc 4.41 function in current mmc driver.

hw reset ,partitiing, enhanced area setting, boot partition update etc..

If mmc have ioctl for emmc 4.4.1 functions, mmc user feel convenient.

Is there a plan supported emmc 4.41 fuctions ?

Thanks.

Re: mmc ioctl for hw reset ,partitiing, enhanced area setting, boot partition update.

[Andrei Warkentin]

On Wed, Mar 30, 2011 at 12:23 AM, NamJae Jeon <linkinjeon@gmail.com> wrote:
> Dear. Chris.
>
> you know, there is no method to use emmc 4.41 function in current mmc driver.
>
> hw reset ,partitiing, enhanced area setting, boot partition update etc..
>
> If mmc have ioctl for emmc 4.4.1 functions, mmc user feel convenient.
>
> Is there a plan supported emmc 4.41 fuctions ?
>
> Thanks.
> --

I have sent a patch to support accessing partitions other than the
user area ([RFC] MMC: MMC boot partitions support),  The first part
just adds the required changes and enables the boot partitions. I
didn't want to add everything before I got the core changes reviewed,
commented and hopefully approved.

Actually the ioctl to support creating new device partitions will be
interesting because that will affect the size of the user area, so it
would need to be rescanned. Obviously performing something like that
on an MMC with a filesystem could be deleterious...

What about hardware reset? It's more-or-less equivalent to powering
off the bus from the SD controller... Why would you want to expose
that through an ioctl?

A

Re: mmc ioctl for hw reset ,partitiing, enhanced area setting, boot partition update.

[Andrei Warkentin]

Hi,

On Wed, Mar 30, 2011 at 10:11 AM, NamJae Jeon <linkinjeon@gmail.com> wrote:
> usally, bootloader is stored in boot partition. I suggested ioctl to
> update bootloader in boot partition not modifing boot partition size.
>

Maybe I didn't explain myself clearly enough, sorry. The patch I have
exposes the boot partitions
as block devices and you can read and write to them without affecting
the rest of the MMC card.

> and moviNAND(samsung) is needed by boot parittion size setting. and
> when boot parition size is changed, all user data will be reset, it
> will be initial status.
>
> but iNAND(sandisk) is not needed it. boot partition size is fixed(1MB).
>

I am unsure what you're talking about. The eMMC 4.41 spec (see 7.2)
does not allow changing boot partition size.
It is fixed to a certain size, and that size is specified by the
BOOT_SIZE_MULTI field in EXT_CSD. For the Toshiba devices
I have around me (MMC08G, MMC16G and MMC32G), each boot partition (two
total) is 2MB in size.

I don't think ioctl for accessing device partitions is a good idea,
because the device partitions are just block devices, so they should
be exposed as such.

For device partitioning, to support create General Purpose partitions
(up to 4), an ioctl is probably needed. You could look at "[PATCH
resend] mmc: Added ioctl to let userspace apps send ACMDs" by John
Calixto which was last send March 17th. That's generic enough to
support partitioning (which is a one time programming procedure
anyway...so there may be no value of adding a specific ioctl for it,
considering how dangerous of an operation it is).

A

Re: mmc ioctl for hw reset ,partitiing, enhanced area setting, boot partition update.

[NamJae Jeon]

Hi. Andrei.

Can I know current status of progress accepting partition mangement patch ?

Thanks.

2011년 4월 4일 오후 9:13, Andrei Warkentin <andreiw@motorola.com>님의 말:
> When the boot partitioning patch is accepted, there will be a short
> patch to add GP partitions in.
>
> Thanks,
> A
>
> 2011/4/4 NamJae Jeon <linkinjeon@gmail.com>:
>> Hi. Andrei
>>
>> I checked this patch [RFC] MMC: MMC boot partitions support). Can it
>> support gerneal purpose partition ? Boot partition be only supported
>> in this patch.
>>
>> Is there another patch for general purpose partitions ?
>>
>> Thanks.
>>
>> 2011년 4월 3일 오후 12:03, NamJae Jeon <linkinjeon@gmail.com>님의 말:
>>> Thanks for your reply.
>>>
>>> 2011. 4. 1. 오후 4:58에 "Andrei Warkentin" <andreiw@motorola.com>님이 작성:
>>>
>>>>
>>>> I highly suggest you read the relevant section in JEDEC eMMC spec, which
>>>> is free.
>>>>
>>>> Writeable attributes in EXT_CSD are manipulated through CMD6.
>>>>
>>>> Thanks,
>>>> A
>>>>
>>>> On Apr 1, 2011 2:51 AM, "NamJae Jeon" <linkinjeon@gmail.com> wrote:
>>>> > Hi. Andrei.
>>>> >
>>>> > For partitioning, you suggest I try to use ioctl of ACMD.
>>>> >
>>>> > I don't understand your means. because EXT_CSD is changed for
>>>> > partitioning not CMD.
>>>> >
>>>> > Would you plz explain more ?
>>>> >
>>>> > Thanks.
>>>> >
>>>> > 2011/3/31 NamJae Jeon <linkinjeon@gmail.com>:
>>>> >> Hi, Andrei.
>>>> >>
>>>> >> Thanks. I will check your information.
>>>> >>
>>>> >>
>>>> >> 2011/3/31 Andrei Warkentin <andreiw@motorola.com>:
>>>> >>> Hi,
>>>> >>>
>>>> >>> On Wed, Mar 30, 2011 at 10:11 AM, NamJae Jeon <linkinjeon@gmail.com>
>>>> >>> wrote:
>>>> >>>> usally, bootloader is stored in boot partition. I suggested ioctl to
>>>> >>>> update bootloader in boot partition not modifing boot partition size.
>>>> >>>>
>>>> >>>
>>>> >>> Maybe I didn't explain myself clearly enough, sorry. The patch I have
>>>> >>> exposes the boot partitions
>>>> >>> as block devices and you can read and write to them without affecting
>>>> >>> the rest of the MMC card.
>>>> >>>
>>>> >>>> and moviNAND(samsung) is needed by boot parittion size setting. and
>>>> >>>> when boot parition size is changed, all user data will be reset, it
>>>> >>>> will be initial status.
>>>> >>>>
>>>> >>>> but iNAND(sandisk) is not needed it. boot partition size is
>>>> >>>> fixed(1MB).
>>>> >>>>
>>>> >>>
>>>> >>> I am unsure what you're talking about. The eMMC 4.41 spec (see 7.2)
>>>> >>> does not allow changing boot partition size.
>>>> >>> It is fixed to a certain size, and that size is specified by the
>>>> >>> BOOT_SIZE_MULTI field in EXT_CSD. For the Toshiba devices
>>>> >>> I have around me (MMC08G, MMC16G and MMC32G), each boot partition (two
>>>> >>> total) is 2MB in size.
>>>> >>>
>>>> >>> I don't think ioctl for accessing device partitions is a good idea,
>>>> >>> because the device partitions are just block devices, so they should
>>>> >>> be exposed as such.
>>>> >>>
>>>> >>
>>>> >>> For device partitioning, to support create General Purpose partitions
>>>> >>> (up to 4), an ioctl is probably needed. You could look at "[PATCH
>>>> >>> resend] mmc: Added ioctl to let userspace apps send ACMDs" by John
>>>> >>> Calixto which was last send March 17th. That's generic enough to
>>>> >>> support partitioning (which is a one time programming procedure
>>>> >>> anyway...so there may be no value of adding a specific ioctl for it,
>>>> >>> considering how dangerous of an operation it is).
>>>> >>>
>>>> >>> A
>>>> >>>
>>>> >>
>>>
>>
>